Nearly two months after stepping down as head coach at McMurry University in Abilene (and a month after it was first reported), offensive football guru Hal Mumme is bound for Highland Park, where he will serve as SMU head coach June Jones’ top assistant and “passing game coordinator.”

Mumme, who originally mentored Leach at Iowa Wesleyan, was born in San Antonio, attended high school in Dallas and ultimately got his college degree from Tarleton State. His speedy, passing-heavy “Air Raid” offense has essentially been the modern version of the “run-and-shoot,” which Jones and Mouse Davis pioneered at both the college and pro level.

As the Abilene Reporter-News noted, “three of the top seven quarterbacks in career passing yards per game were coached by Jones or Mumme”: Hawaii’s Colt Brennan and Timmy Chang, and New Mexico State’s Chase Holbrook.

Mumme has coached in Texas at both the high school (Aransas Pass, Copperas Cove) and college (West Texas State, UTEP) level. His apex in the college game was at Kentucky, where Leach was his coordinator for two seasons and quarterback Tim Couch set a number of SEC records, though Mumme’s stint there ended with NCAA sanctions for the program.

Mumme figured prominently in Sam Gwynne’s September 2009 cover story profile of Leach, then on top of the world at Texas Tech.

Mumme, as it turned out, was on to a big idea. He was a disciple of LaVell Edwards’s, the brilliant Brigham Young coach who in the eighties was lighting up college football with the most potent passing attack in history, one that won him a national championship in 1984. Mumme had studied Edwards’ schemes closely, and at Copperas Cove he had put those ideas to work. He installed a radical offense that featured widely split linemen, passed on most downs, and used four or five receivers. In less than two years he had turned Cove into one of the state’s most prolific passing offenses, knocking off such powerhouses as Austin Westlake, Killeen Ellison, and Temple—which had beaten Cove 70-0 the last time they’d met. Each spring Mumme made a pilgrimage to BYU, where Edwards would open the film room to him.

By the time Mumme arrived at Iowa Wesleyan, he knew exactly what he wanted to do. Leach hit it off with him immediately, meeting at BYU in the spring to watch practice and later spending most of his free time driving with Mumme all over the country to study other teams’ passing schemes. “Hal was really driven as far as studying football,” Leach said. “We’d drive through snowstorms and rainstorms. We’d go to some little high school that had something we were interested in seeing. We would go visit the Chicago Bears, the Green Bay Packers. We would weasel our way into the Packers offices, and [head coach] Lindy Infante would talk to us. We went to countless colleges, anywhere that had somebody who was throwing the ball.” Though Leach was the student and Mumme the master, the two men developed their offense together. “We spent a lot of time talking on our trips,” said Mumme, who now coaches at McMurry University, in Abilene. “Florida is a long way from Iowa.”

At Iowa Wesleyan they put their theories to work. In 1989 they began adopting the shotgun as their primary formation. In 1991 they installed a no-huddle offense. Like theoretical physicists, they began to investigate the nature of time. “We just saw time differently than other coaches did,” said Mumme. “You can replace personnel. You can replace equipment. Time is the only thing you can’t replace in a game. So we wanted to run as many plays as we could in the time allotted.” Most teams want to eat up the clock, using ball control to increase their time of possession. Mumme and Leach wanted nothing to do with slowing down the game. Time of possession did not matter. Running ninety plays did. Scoring quickly did. The game itself—now with up to five receivers streaking across the field on almost every play—became faster.

And all of it was based on simplicity. Where many so-called genius offensive coaches keep thick playbooks, Mumme and Leach had no playbook. They ran roughly twenty basic plays, which they disguised by running them out of different formations: double tight ends, four-receiver spread, two running backs, et cetera. The routes the receivers ran were the same, but of course the defense did not know that. To the defense, each play looked more hellishly complicated than the last. Mumme and Leach’s rule was that if they added a play, they had to subtract one. Their idea was to keep things as simple as possible for their players. The simplicity helped with the speed too. As former University of Texas coach Darrell Royal once observed, “If a player is the least bit confused, he can’t be aggressive. Tattoo that on your wall. Or better still, on your wallet.” Confused players could not, as Leach would say, play fast.

The result was startling. Iowa Wesleyan had gone 0-10 the year before Mumme and Leach arrived. Over the next three years the program went 25-10. In 1991 Mumme’s Tigers became the first team in school history to make the National Association of Intercollegiate Athletics playoffs, with a 10-2 record. The 1990 team led the nation in passing offense; in 1989 and 1991 it finished second. Over a three-year stretch, Iowa Wesleyan quarterbacks threw for more than 11,000 yards and broke 26 national records. For Leach, who considers Mumme “one of the greatest coaches there is,” it was a formative experience.

At SportsIllustrated, Holly Anderson has solicited names from her Twitter followers for the newest version of the Mustangs offense. Among the suggestions: “Air Stang,” “Wild Verts Can’t Be Broken” and her own headline, “Raid-N-Shoot” (I don’t think SMU wants anything with “raid” in it, however).

Prior to taking over at McMurry in 2009, Mumme was at New Mexico State, where he was accused of discriminating against four Muslim players who read from the Koran while the rest of the team recited the Lord’s Prayer (a lawsuit was settled with no admission of wrongdoing).

Mumme went just 11-38 over four years in Las Cruces (the website for his football camp omits that part of the resume), but his lower-level comeback at McMurry went much better. He went 27-16 in four years, and the War Hawks made the transition from Divison III to Division II last season.

Mumme’s close relationship with Leach also prompted him to take some hard shots at former SMU star Craig James in 2011.

“Craig James is an (expletive), and everybody in Texas knows it. His son’s an (expletive), and you can quote me. I was at New Mexico State, and we turned (Adam) down. Nobody would give that guy a scholarship except Mike Leach.”